Sistemas de integração e qualidade do solo e da água na Amazônia oriental.

Abstract

Integrated systems have become common in several regions of the planet and studies on the effects of these systems on soil attributes have intensified. However, there are still doubts about its impacts on the environment, due to the use and management applied. In this sense, the objective of this thesis was to determine and evaluate the water quality and the impacts on the chemical and physical attributes of the soil of crop-livestock-forest integration systems, continuous pasture, homogeneous mahogany forest compared to a secondary forest used as a control under high and low rainfall in a period of 2 years in an area located in the municipality of Terra Alta, PA in the Experimental Field of Embrapa Amazônia Oriental. Where collections were carried out in periods of low and high rainfall. For analysis of soil physical attributes (soil density, total porosity, macro and microporosity), soil samples were collected at depths of 0-5, 5-10 and 10-15 cm. To evaluate the chemical attributes of the soil (pH, Ca, Mg, K, P, Al, H+Al, CTC pH7, V% and organic matter), to evaluate the quality of the water, analyzes of its physical-chemical parameters were carried out. , such as pH, electrical conductivity, alkalinity, hardness, acidity, turbidity, color, major ions and nutrients, such as Ca2+, Mg2+, Na+, K+, Cl and SO4 2-, NO 3- , NO2- , NH4+ and PO43- located in the area of direct influence of the experiment, upstream and downstream of it. Data were subjected to principal component analysis. The results were submitted to the normality test to perform the Tukey test to compare the means at a 5% probability level. The results showed that there was a variation in the physical-chemical attributes of the soils with their different uses and in different periods. An increase in chemical attributes (M.O, K, Ca and Mg) was observed in systems associated with forest components IPF-T, IPF-M and FM, especially in rainy periods. As for the physical attributes, the ILPF with the Teak forest component (IPF-T) and the African Mahogany (FM) homogeneous forest system presented the values of Ds, Pt and Ma closer to the control, or the pasture was better. in the recovery of the physical attributes of the soil when compared to the other systems. Regarding the water quality, the influence of seasonality in the studied parameters was observed, related to soil leaching with pH and ammonia values, above the appropriate level, especially in the rainy season of the second year of the experiment.